applied hydrology rslab-ntu lab for remote sensing hydrology and spatial modeling 1 flood routing...
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![Page 1: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/1.jpg)
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Applied Hydrology
RSLAB-NTU
Lab for Remote Sensing Hydrology and Spatial Modeling
Flood Routing & Detention Basin Design
Professor Ke-Sheng ChengDept. of Bioenvironmental Systems Engineering
National Taiwan University
![Page 2: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/2.jpg)
2Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
The storage effect
The storage effect of a water-retention structure or a channel reach can change the shape of the inflow hydrograph. Therefore two types of routing procedures are needed to calculate the outflow hydrograph. Level-pool routingChannel routing
![Page 3: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/3.jpg)
3Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Level-Pool Routing (Reservoir Routing)
For a reservoir the outflow is uniquely controlled by the water depth (or stage) of the reservoir pool. Also, the reservoir storage is a single-value function of the stage.
Flow velocity in the reservoir is usually very low.
![Page 4: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/4.jpg)
4Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Comparison of flow routing under invariable and variable stage-discharge relationships
Invariable S~Q relationship Variable S~Q relationship
![Page 5: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/5.jpg)
5Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Discharge under variable S~Q relationship
![Page 6: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/6.jpg)
6Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Reservoir routing
Modified puls method (Storage indication method)
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7Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
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8Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
![Page 9: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/9.jpg)
9Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
An example
Given the following storage-outflow relationship and inflow hydrograph, calculate the outflow hydrograph. (Use 10-minute routing interval).
![Page 10: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/10.jpg)
10Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Stage~storage~outflow relationship
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11Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
![Page 12: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/12.jpg)
12Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Reservoir routing as a computation of mass balance
For a reservoir the outflow is uniquely controlled by the water depth (or stage) of the reservoir pool. Also, the reservoir storage is a single-value function of the stage.
As a result, given a stage the reservoir storage and outflow can be uniquely determined, if the stage~storage and stage~outflow relationships are known.
An intuitive trial-and-error approach for reservoir routing can be implemented.
![Page 13: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/13.jpg)
13Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Alternative solution
Stage~storage
Stage~discharge
![Page 14: Applied Hydrology RSLAB-NTU Lab for Remote Sensing Hydrology and Spatial Modeling 1 Flood Routing & Detention Basin Design Professor Ke-Sheng Cheng Dept](https://reader036.vdocuments.us/reader036/viewer/2022081811/55147f4e550346ea6e8b48b4/html5/thumbnails/14.jpg)
14Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Spreadsheet calculation
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15Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Inflow-outflow-(10*storage)
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16Lab for Remote Sensing Hydrology and Spatial ModelingRSLAB-NTU
Channel routing